The method of this invention relates to the halogenation of organic compounds using trialkyl phosphate or similar compound to mediate the reaction. This reaction system and certain products obtainable thereby are described in United States Pat. No. 3,988,369. See, also, Pearson et al, Synthesis, No. 9 (1976) 621-624; and Pearson et al, Synth. Commun. 9, 5-10 (1979). As described in U.S. Pat. No. 3,988,369, phosphorus pentoxide may be present during the halogenation reaction. None of the cited prior art references describe the halogenation of cyclic acetals or similar compounds.